This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Our long-term goal is to identify molecular tools for increasing biomass production by understanding the molecular and biochemical mechanisms of brassinosteroid (BR) regulation of plant growth and development. Our strategy to achieve this goal is to identify BR-regulated proteins using proteomic methods, and then study their functions using molecular genetic and biochemical approaches. The specific goals of this proposal include: (1) illustrate the functions of a number of BR-regulated proteins identified by proteomic analysis;(2) identify interacting proteins of the BR-regulated protein using affinity purification and mass spectrometry;(3) identify additional BR early response proteins using prefractionation followed by 2-D DIGE and iTRAQ mass spectrometry;(4) determine the functions of a number of the newly identified proteins.